1. Field of the Invention
The present invention concerns a system for identifying and tracking three-dimensional objects by utilizing a distributed system of thin-clients connected to cameras and a server which creates a three-dimensional visual hull for the objects recorded by the cameras.
2. Description of the Related Art
Typically, object detection using cameras is performed by a single stereo-type camera which sends the image information to a central processor that performs two-dimensional filtering and uses object templates to determine the position of an object. Other known camera systems include the use of multiple cameras wherein the image data from each camera is sent to a central processor that determines foreground centroid coordinate information for each camera and then triangulates the position of each object based on the collective centroid coordinate information.
The foregoing known techniques suffer from the problem of either using only two-dimensional data in the first example, or using only three-dimensional centroid estimates in the second example, both of which are known to result in unreliable object position estimates. In addition, both techniques fail to construct three-dimensional volumes of the objects being tracked to provide a more reliable estimation of the object size and movement relative to the background of the camera image. The aforementioned techniques also often have difficulty when attempting to track multiple objects, especially when the objects are near each other. Finally, the foregoing techniques are processing intensive because they use a central processor for performing all image processing and they are therefore limited in scalability.